The long term objective of this research is to understand the etiology of senile cataract in the human. To this end we propose to examine the lipid/protein interactions in normal and cataractous human lenses using fluorescence spectroscopic techniques. Previous work has implicated the lens fiber cell plasma membrane as a possible locus for the primary event(s) of cataractogenesis, and our recent observations are consistent with this hypothesis. In order to extend this work, we propose to reconstitute lipids and proteins from normal and cataractous human lenses, and compare the physical properties of these reconstituted menbranes to the original membranes. Separation of lens lipids from the membrane proteins will be accomplished using detergent extraction. Membrane proteins solubilized in this way will be added to detergent solutions of lipids, and the excess detergent will be removed by dialysis. This method has been successfully used to reconstitute membrane proteins in a variety of biological and non-biological lipid species. The fluorescence polarization of cis and trans parinaric acid probes will then be analyzed in these reconstituted membranes. Using this technique, valuable information regarding the relative motion and distribution of membrane lipids can be obtained. Specifically, we hope to test the hypothesis that lipid/protein interactions are less ordered in the cataractous human lens membrane. The biophysical reconstitution of integral lens membrane proteins will hopefully be a first step toward functional reconstitution of these membranes, and should aid in elucidation of the dysfunction of these membranes in the cataractous state.